This invention is concerned with a method of cooling a blank mould of a glass container forming machine and with a baffle for use in such a method.
In a glass container forming machine in which a parison is formed in a blank mould and is then blown to its final shape in a further mould to which the parison is transferred, the parison is formed either by blowing or by pressing. In either case, the parison is usually formed in an inverted position, i.e. with its neck at the bottom, and is supported by its neck during transfer. The blank moulds of such machines are provided with a baffle which is used whether the parison is formed by blowing or pressing but in different ways. When the parison is formed by blowing, a funnel is positioned on the blank mould to guide a gob of molten glass into the blank mould, once the gob has entered the mould, the baffle is positioned on top of the funnel so that air passages in the baffle communicate via the funnel with the interior of the mould and air is blown into the mould through the passages so that the gob is pressed downwards in the mould by the "settle blow" air, next the baffle is raised and the funnel is removed, then the baffle is positioned on top of the mould so that the air passages are closed by contact with the mould and a surface portion of the baffle closes the top of the mould, and the parison is then blown with the surface portion of the baffle cooperating in shaping the parison. When the parison is formed by pressing, it is not necessary to blow the gob downwards in the mould and, therefore, the baffle is not positioned on the funnel but is positioned on the mould after removal of the funnel. When the parison is pressed, the baffle either has no air passages or such air passages are not used.
In both the above-mentioned methods of forming a parison, difficulty is experienced in adequately cooling the mould since the area containing the most glass and having the least contact time and therefore requiring the most cooling is at the top of the blank mould and not accessible to cooling means other than air blown on to the outside of the mould. Furthermore, it is difficult to control the amount of cooling achieved by air blown on to the outside of the blank mould especially if it is desired to cool some portions of the mould more than others.
It is an object of the present invention to provide a method of cooling a blank mould of a glass container fforming machine in which consistent and controlled cooling of the top portion of the blank mould can be achieved.